/*
 * Copyright (c) 2015, ARM Limited and Contributors. All rights reserved.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */

#ifndef EXT_H_
#define EXT_H_

#include "key.h"
#include <openssl/x509v3.h>

/* Extension types supported */
enum ext_type_e {
    EXT_TYPE_NVCOUNTER,
    EXT_TYPE_PKEY,
    EXT_TYPE_HASH
};

/* NV-Counter types */
enum nvctr_type_e {
    NVCTR_TYPE_TFW,
    NVCTR_TYPE_NTFW
};

/*
 * This structure contains the relevant information to create the extensions
 * to be included in the certificates. This extensions will be used to
 * establish the chain of trust.
 */
typedef struct ext_s {
    const char *oid;    /* OID of the extension */
    const char *sn;        /* Short name */
    const char *ln;        /* Long description */
    const char *opt;    /* Command line option to specify data */
    const char *help_msg;    /* Help message */
    const char *arg;    /* Argument passed from command line */
    int asn1_type;        /* OpenSSL ASN1 type of the extension data.
                 * Supported types are:
                 *   - V_ASN1_INTEGER
                 *   - V_ASN1_OCTET_STRING
                 */
    int type;        /* See ext_type_e */

    /* Extension attributes (depends on extension type) */
    union {
        int nvctr_type;    /* See nvctr_type_e */
        int key;    /* Index into array of registered public keys */
    } attr;

    int alias;        /* In case OpenSSL provides an standard
                 * extension of the same type, add the new
                 * extension as an alias of this one
                 */

    X509V3_EXT_METHOD method; /* This field may be used to define a custom
                   * function to print the contents of the
                   * extension */

    int optional;    /* This field may be used optionally to exclude an image */
} ext_t;

enum {
    EXT_NON_CRIT = 0,
    EXT_CRIT = !EXT_NON_CRIT,
};

/* Exported API */
int ext_init(void);
ext_t *ext_get_by_opt(const char *opt);
X509_EXTENSION *ext_new_hash(int nid, int crit, const EVP_MD *md,
        unsigned char *buf, size_t len);
X509_EXTENSION *ext_new_nvcounter(int nid, int crit, int value);
X509_EXTENSION *ext_new_key(int nid, int crit, EVP_PKEY *k);

/* Macro to register the extensions used in the CoT */
#define REGISTER_EXTENSIONS(_ext) \
    ext_t *extensions = &_ext[0]; \
    const unsigned int num_extensions = sizeof(_ext)/sizeof(_ext[0])

/* Exported variables */
extern ext_t *extensions;
extern const unsigned int num_extensions;

#endif /* EXT_H_ */
